Clutch control mechanism



Apn w, 1940.

A. A. HODGKINS CLUTCH CONTROL MECHANIYSM Original Filed Dec. l2, 1931INVENTOR A'r'roRNEY Patented Apr. 16, 1940 UNITED STATES CLUTCH ooNraoLM EoHANrsM Albert A.. Hodgkins, Lynn, Mass, assignor` to Bendix ProductsCorporation, South Bend, Ind., a corporation of Indiana Originalapplication December' 12,1931, Serial No. 580,526. Divided and thisapplication March ll, 1937, Serial No. `130,230

2 Claims.

This invention relates broadly to the automatic performance of sluitingmovements by means of power actuators or servo motors. Moreparticularly, the invention relates to the auto- 5 matic control of suchpower actuators of servo motors.

It has heretofore been proposed to provide a pneumatically operatedmotor actuated by the sub-atmospheric pressure in the intake manifold ofan internal-combustion engine, the piston or diaphragm thereof beinglinked to the clutch pedal, say, of a self-propelled vehicle, to causethe setting and release of the clutch by the variations of the uidpressure in the manifold. To

control the operation of the motor, a valve has been provided in thecommunicating passage be tween the engine and the motor, which valve hasbeen actuated mechanically from the throttle of the engine.

An important object of the invention is to provide a simple type ofelectro-magnetically operated clutch operating motor, the control meansfor said motor including a simple, compact and elective pressurediierential operated motor, the latter serving to operate a controlswitch for the motor.

Yet another object of the invention is to provide a pneumaticallyoperated power device for operating a control switch, which device shall3@ be self-actuating and dependent only'upon the degree of gaseouspressure within the intake manifold of an automobile engine. To this endthere is provided a control device susceptible to iiuctuation in thefluid pressure in the intake manifold or cylinders of aninternal-combustion engine. l

These and other objects of the invention and the means for theirattainment will be more apparent from the following detailed descriptionof a preferred embodiment, which description is taken in connection withthe accompanying drawing, in which the sole gure is a view, somewhatdiagrammatic, showing the clutch control mechanism constituting myinvention, said mechanism including a pressure dii'erential operatedswitch operating motor controlling an electrically energized motor fordisengaging the clutch of a motor vehicle.

The invention is illustrated as applied to a clutch control for motorvehicles, although that is only one oi its many applications.

In previous proposals for the control of clutches in motor vehicles, theclutch pedal has been connected to oneside of 'the piston or diaphragmof a vacuum cylinder or servo motor, while the cyl- (Cl. wil-90) inderon the other side of the piston has been in communication with theintake manifold of the engine through apipe which is controlled by avalve. The valve is normally closed by a spring to shut oi the powercylinder from the vacuum in the manifold. Valve operating means isconnected with the foot throttle of accelerator pedal,

so that when the accelerator pedal is released and the accelerator pedalspring returns it to normal position, it opens the valve in the vac- 10uum line and permits the vacuum in the manifold to draw the piston inthe cylinder and thus depress the clutch pedal and release the clutch.When the accelerator is depressed, the Valve closes and the clutch pedalis released to permit .15 the clutch to engage. Among the disadvantagesof this type of clutch control is that it is effective solely whenactuated by the operator of the vehicle and is lnot responsive to theload on the engine and does not automatically release the 20 clutch whenthe momentum of the vehicle is in excess of the speed of the engine.

The present invention when applied as a clutch release for automotivevehicles provides a true free-wheeling in thatthe engine isautomatically .25 declutched from the propeller shaft whenever themomentum of the vehicle exceeds the propulsive effort of the engine.

It has been found that the conditions of subatmospheric pressure orvacuum in an internal- 30 combustion engine fluctuate with the load onthe engine. That is, when there is no load on the engine, thedownwardmovement of the pistons on the intake stroke increases therareiication in the intake manifold and combustion chamber. .35Similarly, this rarecation in the intake manifold and combustion chamberincreases as the throttle valve controlling the `carburetor is closed.Thus, for example, when the vehicle is stationary and the engine idling,the rarecation of atmos- 0 phere, or, as` it is said, the vacuum in themanifold is high. If the throttle is opened, due to the inrush intotheintake manifold and` combustion chamber of the explosive mixture, therarecation or vacuum drops momentarily and then y45 gradually builds upagain as the pistons reciprocate. Thus, when the vehicle commences tomove, iirst because of the opening of the throttle and then because ofthe load on the engine, there results a decrease in the rarecation ofthe at- 50 mosphere or vacuum in the manifold, but as the vehiclegathersmomentum, the load on the engine decreases and the vacuumincreases in the manifold and explosion chambers. Advantage is taken ofthis iiuctuation of the Huid pressure `,55

manifold the fluid pressure fluctuates.

in the manifold and explosion chambers by providing a switch operatingmeans which is susceptible to such fluctuation. In other words, whenapplied to the intake manifold and/ or combustion chambers of aninternal-combustion engine or any other chamber in which the fluidpressure iluctuates, the switch operating means is responsive tofluctuations or variations in the degree of vacuum and is self-openingand closing dependent upon the degree of rarefaction in the chambers.

The invention is illustrated as applied to motor means, preferably anelectro-magnetic or solenoid motor, adapted to actuate or'shift theclutch releasing lever in an automotive vehicle, but it will be readilyapparent `'that the invention is equally applicable to any sort ofcontrolling instrumentality for any purpose. The switch for controllingsaid motor may be oper'ated by a vacuum operated motor: however, it willalso be readily rapparent that -said switch controlling motor may beoperated by any source of fluid pressure in which the `uid pressur'eluctuates. In the illustrated embodiment, the fluctuating fluid`pressureexisting inthe intake manifold and explosion chambers of aninternal-combustion engine is the source, but broadly, any source ofrareed atmosphere vwill be'contemplated and in such br'oadaspect Will bereferredfto as a chamber in which the uid pressure fluctuates, or assuction inducing means.

-Referring now tothe drawing, disclosing a preferred embodiment of' myinvention, movable armature l2 of an-electro-magnetic motor Mis shown asconnected, bylinks 32 an'd 35, with a Aclutch actuating mechanism i8, 20of .a motor vehicle. The link 35 is provided at-its vend with a slot 38cooperating with a pin lllfextending from the end of the link 32 `tothereby provide a lost motion connection. Thevclutch shifting arm I'8 isfixedon the shaft20, as by a set screw 22, and has a lug or protuberance24 thereon. This arm 18 and the shaft 20 to which it is affixed normallyassume the position shown in the figure of the drawing, by virtue of theclutch spring (not shown), which normally urges the clutch -elementsinto engagement. Loosely mounted von the shaft 20 is a foot pedal 26,which is normally retained inthe elevated position by means of aspring'Z. The foot pedal 25 has a bearing surface 3U for engagement withthe protuberance 2li on the arm I8. Thusfwhen the foot pedal 26 isdepressed, the arm I8 is rotated in a counter'- clockwise direction torelease the clutch, but when bthe motormeans hl, next to be described,isoperated, the clutch operating shaft 20 is turned, but the foot pedal26 does'not move.

the switch casing 58.

,The tubular casing of the motor 59 has only ,one port 84, communicatingwith a conduit 60 leading to the intake manifold I 5 of theinternalcombustion engine Il of the vehicle, in which The interior ofthecasing-provides a chamber, indicated by the reference numeral 62, andwithin this chamber there reciprocates a plunger or power element l0,one face 68 of which is subjected to atmospheric pressure through thevent 66. Force is applied to the other side of the plunger by anadjustable spring 16. Attached to the plunger is a rod or finger 3ladapted for engagement by the wiping contact 29 at all times. The casing58, plunger 'lll and rod 3l are yof conductive material and, hence, formpart of the electrical circuit including the generator. When the switch25 is closed the circuit, including the lmotor i4 and generator i6, isthus completed and the motor energized to retract the movable part l2.However, it is only desirable that the circuit be completed when theplunger 'IU is retracted against spring 16 under conditions'of-predetermined high vacuum in the suction in ducing means l5 andhence the rod 3| is covered with non-conductive material 33 at thatplace or all places where the rod 3l contacts with wiper 2li exceptlwhen the rod is retracted within the motor 59 under conditions of highVacuum. Hence, except when the vacuum in theintake pipe, in theillustrated embodiment, reaches the predetermined maximum, the circuitis interrupted by the insulating member 33 interposed between the twocontact members 3l and 29.

In order that the operation of the device may be clearly understood, itmust be appreciated that when the engine is not operating, that'is,.when it is at rest, the fluid pressure of the gaseous contents of theintake manifold is substantially atmospheric pressure because the intakemanifold is in communication with the inlet lof the idling with thetransmission gears out of mesh,

the fluid pressure in the manifold may be found on a gauge to be, say,ten pounds (twenty inches of mercury). When the clutch is released, thepropeller shaft connected through low gear With the engine, the clutchreengaged, and the throttle valve opened, there is a momentary increasein the rfluid pressure, i. e., decrease in the vacuum,l in the manifold,say, to three pounds. As the car gathers momentum, the .vacuum in themanifold increases until it registers ten pounds on the gauge again.This same cycle of conditions occurs at every shift to another gearratio. Again, when the vehicle is traveling along the level, or on adown grade, it frequently happens that the momentum of the car, andhence the revolutions per minute of the propeller shaft, Vexceeds thespeed of rotation of the crank shaft of the engine and hence, the enginebeing relieved of load, the vacuum in the manifold again increases.condition of high vacuum in the intake manifold Vof the engine at timeswhen there is no load on the engine, and at such times there is nooccasion for the engine to be clutched to the propeller shaft of thevehicle. At other times, as in starting and when there is a load on theengine, the propeller shaft must be clutched to the engine and this isat a period of low vacuum in the manifold.

yIn accordance with this invention, the switch It will thus be seen thatthere is al operating motor 59 for accuating the controlling switch forthe moto-r I4 is so constructed as to be actuated by the aforesaidpredetermined high vacuum of the engine to close the switch mechanism,that is, the wiper 29 and contact 3|, to thus effect an energization ofthe motor III.

Normally, in periods of low vacuum in the manifold, the power element'III assumes the inactive position illustrated in the drawing. When thepower element is disposed in such position, the insulating member 33serves to break the circuit interconnecting the generator I6, motor I4and cut-out switch 25. The motor I I is thus deenergized and the clutchsprings function to engage the clutch. This condition obtains so long asthe vacuum in the manifold is below a predetermined maximum.

When the vacuum in the manifold rises to or above a predetermined value,the reduction in fluid pressure on the face 6I of the plunger 'IIIpermits atmospheric pressure, acting through vent 66 on the face 6B ofthe plunger, to overcome the force of the spring 16, and the plunger ismoved to the left until stopped by the piston stop 1I. In such position,the aforementioned circuit is completed to thus energize the motor I4 todisengage the clutch.

It will thus be seen that a construction is provided which, when appliedto the clutch of a selfpropelled vehicle, affords automaticfree-wheeling whenever the prime mover is relieved of load withoutmanual actuation of any instrumentality whatsoever. It will be furthernoted that the controller switch of this invention is applicable withany sort of power actuator or motor or the like for automaticallyactuating mechanical elements, as for instance, automatically setting orreleasing clutch elements, moving steering mechanisms, setting orreleasing brake mechanisms, selectively operating change-speed mechanismor performing other shifting movements under the influence of variationsof fluid pressure, particularly for automotive vehicles operating onland, on or in the water, or in the air or in fact in any situationwhere an internal-combustion engine or other prime mover has a chamberin which the uld pressure fluctuates.

The invention heretofore described is disclosed in my Patent No-2,077,413, issued April 20, 1937, this application constituting adivision thereof.

While one illustrative embodiment has been described, it is not myintention to limit the scope of the invention to that particularembodiment, or otherwise than by the terms of the appended claims.

I claim:

1. In an automotive vehicle provided with an internal-combustion engine,an accelerator and a clutch, power means for operating the clutchcomprising an electro-magnetically operated motor unit operablyconnected with the clutch, means for controlling the operation of saidunit comprising a switch and power means for operating said switchcomprising an automatically operable pressure differential operatedmotor, and fluid transmitting means so connecting said latter means withthe intake manifold of the engine that when the manifold is partiallyevacuated the motor is immediately thereafter also partially evacuatedand accordingly energized to thereby operate said switch to effect adisengagement of the clutch.

2. In an automotive vehicle provided with an internal-combustion engine,an accelerator and a clutch, power means for operating the clutchcomprising an electro-magnetically operated motor unit operablyconnected with the clutch, and further comprising a source of electricalpower, means for controlling the operation of said unit comprising (1) apressure differential operated motor including a xed casing and amovable power element and (2) a switch connected to said latter'element, means interconnecting the electro-magnetically operated motor,the switch and the source of electrical power, together with means foreffecting an energization of the pressure differential operated motor bysubjecting its power element to a diierential of pressure.

ALBERT A. HODGENS.

